1. Field of the Invention
The present invention relates to the field of load measuring devices. More particularly, the present invention relates to the field of load measuring devices incorporated within other mechanical apparatus.
2. Description of the Prior Art
Load measuring devices have been introduced in the past years. The following patents are found to be pertinent to the field of the present invention:
1. U.S. Pat. No. 3,826,321 issued to Rigney et al. on Jul. 30, 1974 for xe2x80x9cLoad Weighing System For Cranes With Rotatable Boomsxe2x80x9d (hereafter xe2x80x9cRigneyxe2x80x9d);
2. U.S. Pat. No. 4,118,012 issued to Kerr et al. on Oct. 3, 1978 for xe2x80x9cLoad Transferxe2x80x9d (hereafter xe2x80x9cKerrxe2x80x9d);
3. U.S. Pat. No. 4,581,947 issued to Wulf et al. on Apr. 15, 1986 for xe2x80x9cLinear Force Measurement Apparatus Or Devicexe2x80x9d (hereafter xe2x80x9cWulfxe2x80x9d),
4. U.S. Pat. No. 4,939,936 issued to Spooner et al. on Jul. 10, 1990 for xe2x80x9cShapemeterxe2x80x9d (hereafter xe2x80x9cSpoonerxe2x80x9d);
5. U.S. Pat. No. 4,958,525 issued to Hauer et al. on Sep. 25, 1990 for xe2x80x9cWeb Tension Measuring Assemblyxe2x80x9d (hereafter xe2x80x9cHauerxe2x80x9d);
6. U.S. Pat. No. 5,479,831 issued to Hirose on Jan. 2, 1996 for xe2x80x9cFishline Tension Measuring Device For Fishing Reelxe2x80x9d (hereafter xe2x80x9cHirosexe2x80x9d); and
7. U.S. Pat. No. 5,970,906 issued to Hrescak et al. on Oct. 26, 1999 for xe2x80x9cMotion Compensation Winchxe2x80x9d (hereafter xe2x80x9cHrescakxe2x80x9d).
Rigney discloses a load weighing system for cranes with rotatable booms. The system uses a boom-mounted dynamometer whose output is an accurate indication of cable tension and therefore load weight. The dynamometer comprises a base plate on which are mounted spaced freely rotatable guide pulleys and an intermediate freely rotatable load cell assembly offset a slight amount from a line joining the centers of the pulleys. The main load lifting cable passes between the load cell assembly and the pulleys. The pulleys guide the cable as it passes through the dynamometer.
Kerr discloses a load transfer device. It includes pulley bearings which are designed to rest on load cells.
Wulf discloses a linear force measurement apparatus or device. It requires a separate and additional measuring ring supported by a support ring of the bearing assembly of a deflection roller over which the web passes. The measuring ring has a pair of slits cut into the ring having parallel rectilinear portions which are in a perpendicular direction of force application.
Spooner discloses a shapemeter. It includes strain gauges provided on webs of the shapemeter.
Hauer discloses a web tension measuring assembly. It requires a separate and additional measuring cage which includes a flanged ring fixed to a side frame of the printing machine and a retainer ring joined to a bearing for the measuring roller. These two rings are connected by a plurality of flectional beams that are provided with strain gauges. Changes in web tension are sensed by the strain gauges in response to deflection of the flectional beams.
Hirose discloses a fishline tension measuring device for a fishing reel. It include strain gauges mounted on a separate and additional bearing support member.
Hrescak discloses a motion compensation winch. It uses a measuring device to measure the tension on a cable.
In many applications there is a need to measure a load applied on a pulley. However, it is desirable to have an in-line measuring device built into or replacing the hub of the pulley for measuring the load, without using additional separate mounting or supporting members for the measuring device.
Therefore, it is desirable to provide a new in-line pulley hub load measuring device which is built into or replaces the hub of the pulley for measuring the load applied on the pulley without adding separate auxiliary members.
The present invention is a novel and unique pulley hub load cell. It is an in-line pulley hub load measuring device which is built into or replaces the hub of the pulley for measuring the load applied on the pulley without adding separate auxiliary members.
It is an object of the present invention to provide a measuring device to measure the load applied on a pulley.
It is also an object of the present invention to provide an in-line load cell built into or replacing the pulley hub of a pulley for measuring the load applied on the pulley.
It is an additional object of the present invention to provide a pulley hub load cell that does not require any additional separate auxiliary member for mounting or supporting the load cell.
It is a further object of the present invention to provide a pulley hub load cell to sense either the shear strain or bending strain exerted on the measuring device.
Described generally, the present invention is a pulley hub load cell assembled inside a hub opening of a pulley between a rolling element part and a pulley axle. The present invention pulley hub load cell has a generally cylindrical shaped body adapted to be placed inside the rolling element part and having an interior bore with two opposite ends for insertion through the pulley axle, and two generally cylindrical sleeve shaped covers for protecting the generally cylindrical shaped body.
The generally cylindrical shaped body of the load cell has an exterior central section to be brought into contact with the rolling element part, and two interior flanges at the two opposite ends of the interior bore of the body respectively to be brought into contact with the pulley axle, forming a cantilever configuration which is deformable when counter-loads are applied to the central section and the interior flanges of the body from the rolling element part and the pulley axle respectively.
The pulley hub load cell is further provided with at least one strain gauge and electronic circuitry element affixed to the body between the central section and one of the two opposite ends of the body for producing and outputting a load sensing signal in proportion to the counter-loads applied to the body.
Further novel features and other objects of the present invention will become apparent from the following detailed description, discussion and the appended claims, taken in conjunction with the drawings.